Prevent it: Eat slowly and chew thoroughly. If you're prone to dyspepsia (the official name for gastric upset), avoid spicy foods and other triggers (see "Seethers & Soothers," below right), large meals—and arguments at the dinner table.

Treat it: All OTC antacids—like Rolaids, Tums, and Maalox—ease heartburn, though liquids may work a little faster than tablets or chewables. If you have GERD, drugs that slash stomach acid help head off repeat heartburn attacks.

Prevent it: To avoid reflux, you should wait three hours after dinner before lying down. This gives your stomach time to empty so nothing comes back up your esophagus. Elevating the head of your bed four to six inches also helps.

3. Feeling Stuck?

What it is:Constipation

Treat it: Stimulant laxatives (Ex-Lax, Correctol) work in six to 12 hours, but can trigger an OMG! I need a bathroom! emergency. Stool softeners (Colace) and psyllium supplements (Metamucil, Konsyl) are gentler and work in 12 to 72 hours. After two weeks, see your M.D. if you still have heartburn or are queasy, crampy, or constipated.

Prevent it: Meds, from antidepressants to pain pills, can be constipating. If you must stay on the Rx, use a stool softener. Calcium and iron can be culprits, too; even if you don't take these as supplements, check your multi.

4. Got the Trots?

What it is: Diarrhea

Treat it: Wait 48 hours to treat. OTC antidiarrheals keep you from dashing to the bathroom, but may slow passage of food-borne or infectious bugs, prolonging your woes. While you wait, chug two quarts of Gatorade or Pedialyte a day to avoid dehydration.

Prevent it: Most cases are due to germs (Wash hands! Wash produce!). But your problem may come from a surprising source: health bars with added "designer" fiber. Check the label for inulin (sometimes listed as "chicory root fiber").

5. Gnawing Pain

What it is: Ibuprofen Issues

Treat it: Motrin, Advil, and other NSAIDs like naproxen sodium (Aleve) and aspirin can irritate your stomach lining, leading to wicked stomach pain. Acetaminophen (Tylenol) is gentler on your tummy.

Prevent it: Try water for a headache (you may be dehydrated) and light exercise, heat, or massage for body aches. Also, you might be able to tolerate NSAIDs if you take them with food.

6. On & Off Misery

What it is: IBS

Treat it: If your tetchy stomach comes and goes and is accompanied by bloating, gas, and constipation or diarrhea, you might have irritable bowel syndrome or a gluten sensitivity. See your regular doctor, who may have you keep a food diary for a week. Seek help for severe cramping, bloody stool or vomiting, dizziness, fever, or a very tender belly.

Prevent it: Gluten sensitivity is the diagnosis du jour, and gluten-free products are everywhere, but don't self-treat. A physician needs to rule out celiac disease and then set you up on an elimination diet to see what's behind your symptoms.

7. Crampy & Gassy

What it is: Lactose Intolerance

Treat it: Could it be your latte habit? You might be able to tolerate the amount of milk in a regular-size coffee drink, but the nearly20 ounces in a venti could be pushing you over your lactose threshold.